How Much Does a Boulder or Stone Retaining Wall Cost to Install?

Average Rock Retaining Wall Costs

Boulder Retaining Wall Cost

For boulder walls, expect to pay a minimum of $20 to $55 per face foot (one square foot of the face of the wall) for labor and materials, as locally sourced boulders require time and expense to move. Most boulder walls aren’t more than two rows high. They’re gravity-style, meaning the weight of the rock holds the ground back behind it. Boulders and rocks are two of the greenest, most natural options.

Gabion Retaining Wall Cost

Gabions are an affordable retaining wall, averaging $5 to $40 per square foot. Gabion walls are blocks made from wire cages filled with rocks or crushed concrete. They’re often used near waterlines or in areas with a shifting landscape, as they can adapt and move with the soil as it shifts, rather than cracking or tumbling. The main cost factor comes from the type of filler you use.

Dry Stacked Stone Retaining Wall Cost

Dry stack stone costs $40 to $100 per square foot, depending on the stone you use. You’ll often find it cheapest to use a locally quarried variety, which lowers shipping fees. It’s one of the more expensive walls to build because stacking stone requires proper training and experience.

Fieldstone 

Fieldstone retaining walls cost $25 to $75 per square foot on average. However, the size, accessibility and regional cost factor into the wall’s final price.

Limestone

Limestone retaining walls cost $50 to $100 per square foot. Materials make up about half the price, while delivery and installation make up the rest. They’re often large and heavy and cost about $300 to $400 per ton, plus delivery and installation.

Slate

To install a stone retaining wall made of slate, expect to pay between $30 and $85 per square foot, installed. Slate retaining walls are popular for those who want the traditional dry-stacked stone wall between 2 and 3 feet tall. They're exceptionally strong, resistant to all kinds of damage, and available in varying shades of gray, black, and blue-gray.

Stone Veneer Retaining Walls

Stone veneer retaining walls cost $30 to $80 per square foot. The retaining wall costs vary by wall base and stone veneer type. Usually, the actual wall is a concrete block structure, and the stone veneer is applied over the top to finish the look.

Stone Retaining Wall Cost per Square Foot

Most stone retaining walls cost $25 to $75 per square foot. Many professional landscapers use the “face foot” designation to refer to pricing. A face foot is one square foot of the face of the wall. Cost factors that play into this include:

• The wall’s height

• Type of materials used

• Jobsite accessibility

• Project complexity

Retaining Wall Stone Prices

Stones for retaining walls make up about 50% of the total price. However, the distance of delivery, accessibility of the site, and installation can quickly double or triple what you pay.

Cost of Boulders

Coulders cost between $100 and $600 per ton, which averages out at $400 to $500 per boulder, not including installation. The size, weight, and delivery distance also impact how much you'll pay per boulder. You may also need them drilled, shaped, or placed in difficult areas, increasing the price.

Cost to Build a Stone Retaining Wall

Delivery depends on distance traveled, load size, and other factors. Local delivery for stone ranges from $100 to $200 per load. Labor adds another $10 to $60 per square foot, depending on how you accomplish the project. 

For example, it doesn’t take a lot of work to set delivered stones of similar sizes. But collecting and fashioning a fieldstone wall can take four to five times longer than working with identical stones, increasing labor prices.

Prep and Excavation

There is some preparatory work required when it comes to building a retaining wall that may not be included in the initial price. You'll need to clear the site, excavate for the footing, pay for permits, landscaping, and other tasks necessary to get the best finish for your retaining wall. 

• Cost to excavate: $50–$200 per cubic yard, or $40–$150 per hour

• Cost to remove trees: $200–$1,500

• Cost of landscaping: $300–$16,000

• Cost of permits: $400–$2,000

• Cost of landscape lighting: $2,000–$4,000

Geogrid

Geogrid increases labor costs by up to 50%, but creates a stronger, more durable wall. Geogrid is a flexible mesh that helps to stabilize soil behind a retaining wall. It’s particularly useful where the wall is made from lighter materials, soil is fine and sandy, or the area behind the wall slopes, leading to greater pressure on the wall from the soil it's holding back. 

Contractors excavate the entire distance behind the wall that requires reinforcement. This distance varies based on soil conditions, slope gradient, and wall material. An installer adds a layer of base material, compacts and levels it, and adds the geogrid at the bottom of the trench and beneath where the wall's base blocks will sit. They’ll also add drainage at this time. Then, they’ll build the wall and compact the backfill in the excavated area. 

DIY vs. Hire a Stone Retaining Wall Builder

For these jobs, you’ll likely always hire a professional. Stacking stone properly requires not only experience, but also heavy machinery. Local landscapers and retaining wall contractors have all the experience and equipment necessary to get your project done in a matter of days.

FAQs

What are the advantages of gabion retaining walls?

The main advantages of a gabion are price and the ability to DIY the project. You can fill the metal cages with almost any type of stone, even crushed concrete. They're also quick to construct because of their mesh and loose-fill design. 

They offer good drainage, too, as the loose-filled rocks create a permeable zone that allows water to percolate down to the ground. And, for use on a slope, gabions stabilize soil, helping to limit erosion and reduce water run-off velocity. 

Do gabion walls need foundations?

Gabion walls typically neither need nor have foundations. But there's still some below-ground work required, otherwise these walls would just topple over with minimal stress. You'll at least need a level, compacted base course of gravel a minimum of one inch thick. In areas with loose, fine, or weak soil, you may want to install geogrid to reinforce and strengthen the area. And, where retaining walls combat erosion or hold back soil, you'll need a base course of at least two inches that's twice as wide as the wall itself to add strength and stability.

How long do stone retaining walls last?

Stone retaining walls can last anywhere from 50 to 200 years or more. When done properly, they can stand for hundreds of years. In fact, some dry-stone walls date back well over 700 years. How long your walls last depends on what they're holding back, their materials, how much damage they sustain, whether they have a good foundation, if geogrid or similar reinforcement is in place, and their height. 

Do you need to add drainage for a boulder retaining wall?

Theoretically, no, you don't need added drainage for a boulder retaining wall because water can percolate over the boulders and into the ground. Because the wall is permeable, water doesn't back up behind it and cause foundation problems or erode the soil, particularly where geogrid is in place. 

However, if you have particularly heavy soil prone to waterlogging, or you have a tall wall without geogrid reinforcement, it's advisable to add drainage at the base of the wall that directs water away from the wall foundations.

What is a human-sized boulder?

A human-sized boulder is a rough measurement of boulder weights and sizes. A one-person boulder is a fairly small landscaping boulder measuring up to 12 inches and weighing between 20 and 150 pounds. A two-person boulder measures up to 18 inches and weighs between 150 and 500 pounds. A three-person boulder measures up to 16 inches and weighs between 500 and 800 pounds.